This invention relates to a retractor adapted for use with a safety belt in a vehicle or craft. Such a retractor may be mounted on the floor or on the frame of a vehicle or craft for use by occupants of the vehicle or craft including the driver and passengers. Such vehicles or crafts include automobiles, trucks, buses, railroad trains, aircraft and marine craft. The safety belt retractor is normally unlocked when the safety belt is being withdrawn and buckled about the user and is automatically locked in response to forces which develop during dangerous or emergency conditions, such as a collision. More particularly, this invention relates to a retractor having an actuating mechanism for emergency-locking which is dual sensitive, that is, responsive to two different types of forces: (1) forces applied to the vehicle and to the retractor within the vehicle; and (2) forces applied to the safety belt. Thus, the safety belt retractor of this invention is both vehicle-sensitive and belt-sensitive. The retractor is vehicle-sensitive because it will automatically lock in response to forces applied to the vehicle, and to the retractor because it is located within the vehicle, such as when the vehicle is tilted or overturned. The retractor is belt-sensitive because it will automatically lock in response to acceleration in withdrawal, that is, unwinding, of the safety belt from the retractor, such as when the user lurches forward against the seat belt at the moment of impact during collision. Still more particularly, this invention relates to a retractor having an improved and simplified design in which the vehicle-sensitive portion of the actuating mechanism and the belt-sensitive portion of the actuating mechanism are commonly mounted on a single plate.
Prior art seat belt retractors usually have a reel, biased in the rewind direction, to which a safety belt is attached for retraction. The reel is normally unlocked during ordinary driving conditions, even though the belt is buckled about the user. Thus, the belt may be withdrawn or retracted according to the normal movements of the user. One or more locking devices are provided to prevent further withdrawal of the belt and restrain the user in his seat in response to forces that develop during dangerous conditions. The state of the art in emergencylocking, vehicle safety seat belt retractors is exemplified by: U.S. Pat. No. 3,918,658 of Herbert R. Beller, entitled "Seat Belt Retractor having Inertial Device Activated by Two Stimuli" filed on June 15, 1973; U.S. Pat. No. 3,858,824 of R. L. Stephenson, entitled "Dual Action Safety Seat Belt Retractor" filed Mar. 27, 1973; and U.S. Pat. Nos. 3,180,456; 3,122,339; and 3,122,338 to Whittingham; and 3,489,367 to Kovacs.